The runtime cannot find the main class solution after eclipse imports a new project

Recently in the study of multi-threading, today under a set of source code, import into eclipse, casually found a class with main () tried, can't find the main class.

The first solution is to clean the project, and it is useless. Went online to find a time and finally found a way to work. Here's how:

Remove the Java compiler-->building-->abort build when build path errors occur before the Properties property
That's OK.

Method Reference Address: http://cancait.blog.163.com/blog/static/2133574420081023032064

The landlord test, very good!

The runtime cannot find the main class solution after eclipse imports a new project